1. Field of the Invention
This invention relates to control centers and more particularly to insulated and isolated bus bars therein.
2. Description of the Prior Art
In modern electrical apparatus there is increased attention devoted to operator safety as well as minimizing damage to equipment due to short-circuits. In particular, where electrical bus bars are so disposed that accidental personal contact could occur, then either steel barriers or insulating barriers are provided. Existing designs vary considerably both in execution and in the degree of safety provided by the barriers. However, the existing state of the art has a particular aspect in common, they all create a pocket of air around the bus bars. The size of the air pocket can be quite large so that the bars are regarded to be in a chimney. On the other hand, where the size of the air pocket is quite small, the air is trapped. Patents disclosing insulated bus bars in various aspects are U.S. Pat. Nos. 3,096,131, 3,113,820, 3,170,092, and 3,840,785.
Some constructions of insulated bus bars are thermally inefficient because it is difficult to remove heat from hot bars across an insulating and/or trapped pocket of air. Air chimneys generally do not work well because of restrictions that impede significant air flow.
Associated with the foregoing has been a problem of isolating adjacent bus bars from each other to prevent the initiation or propagation of fault currents. Moreover, there is a need for elimination of damage due to arcing and tracking between the bus bars.